There is available equipment for wafer optical inspection to detect defects on the front-side surface and/or backside. In general, such equipment is using optical microscopic image capture, where the defects are detected in high to medium resolution (such as the Falcon inspection system of Camtek Ltd., Israel). Another approach is laser scan, where irregularities in the scattering pattern are detected as defects.
The above systems and methods illuminate the wafer by a small spots of light and utilize high resolution optics, highly accurate mechanics (including precise X, Y or R-theta stages) and powerful processors. This increases the cost of these systems.
There is a growing need to provide low cost inspection system that will be able to detect “global” phenomena such as lack of photoresist, contamination and the like.
There is a growing need to provide low cost inspection system that will be able to detect “global” phenomena such as overall contamination of a backside of a wafer.